The area of origin is the area in three-dimensional space where the blood source was located at the time of the bloodletting incident. The area of origin includes the area of convergence with a third dimension in the z direction. Since the z-axis is perpendicular to the floor, the area of origin has three dimensions and is a volume.
The term point of origin has also been accepted to mean the same thing. However, it has been argued, there are problems associated to this term. First, a blood source is not a point source. To produce a point source the mechanism would have to be fixed in three-dimensional space and have an aperture where only a single blood droplet is released at a time, with enough energy to create a pattern. This does not seem likely. Second, bodies are dynamic. Aside from the victim physically moving, skin is elastic and bones break. Once a force is applied to the body there will be an equal and opposite reaction to the force applied by the aggressor (Newton's third law of motion). Part of the force will move the blood source, even a millimetre, and change the origin while it is still producing blood. So the source becomes contained in a three-dimensional volume, or region.
As with the area of convergence, the area of origin is easily calculated by using BPA software. There are other longer, mathematical methods of determining the area or origin, one of which is the tangential method.
IABPA definition:
- Point (Area) of Origin - The common point (area) in three-dimensional space to which the trajectories of several blood drops can be retraced. (see figure 5)
Read more about this topic: Bloodstain Pattern Analysis
Famous quotes containing the words area of, area and/or origin:
“Now for civil service reform. Legislation must be prepared and executive rules and maxims. We must limit and narrow the area of patronage. We must diminish the evils of office-seeking. We must stop interference of federal officers with elections. We must be relieved of congressional dictation as to appointments.”
—Rutherford Birchard Hayes (1822–1893)
“If you meet a sectary, or a hostile partisan, never recognize the dividing lines; but meet on what common ground remains,—if only that the sun shines, and the rain rains for both; the area will widen very fast, and ere you know it the boundary mountains, on which the eye had fastened, have melted into air.”
—Ralph Waldo Emerson (1803–1882)
“Though I do not believe that a plant will spring up where no seed has been, I have great faith in a seed,—a, to me, equally mysterious origin for it.”
—Henry David Thoreau (1817–1862)